The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
As is known in itself, an aircraft engine, which is generally of the turbojet engine type, is placed inside a nacelle, which, among other functions:                provides the aerodynamic fairing for the engine,        makes it possible to channel outside air toward the engine,        makes it possible to connect the engine to the aircraft.        
Traditionally, the connection of the engine to the aircraft is done using a support structure comprising two upper longitudinal beams, often called 12 o'clock beams due to their position at the apex of the nacelle, two lower longitudinal beams, traditionally called 6 o'clock beams due to their position in the lower part of the nacelle, and an assembly with a substantially annular shape called the front frame, in reality made up of two half-frames each extending between said upper and lower longitudinal beams, and designed to be fastened to the periphery of the downstream edge of the fan case of the engine.
Such a traditional configuration is shown in FIG. 1 appended hereto, whereof a rear nacelle portion is shown in this case incorporating a thrust reverser, said rear portion comprising:                two 12 o'clock beams 1a, 1b,         two 6 o'clock beams 2a, 2b,         two front half-frames 3a, 3b, each respectively extending between the 12 o'clock beams 1a, 1b and the 6 o'clock beams 2a, 2b, and supporting cascade vanes 5a, 5b,         two half-cowls 7a, 7b each respectively slidingly mounted on a 12 o'clock beam 1a, 1b and on a 6 o'clock beam 2a, 2b, so as to be able to expose the cascade vanes 5a, 5b so as to perform the thrust reversal.        
As is known in itself, during thrust reversal, the air A1 coming from the fan (not shown) and circulating inside the secondary flow tunnel 9a, 9b passes through the vanes 5a, 5b and is expelled toward the front of the nacelle, as indicated by the arrow A2.
Each left and right assembly respectively formed by a 12 o'clock beam, the associated front half-frame, and a 6 o'clock beam, is a rigid assembly with a structural function for the thrust reverser: one such assembly is shown in FIG. 2 (assembly on the left half of the reverser).
As shown in the appended FIGS. 3 and 4, each 12 o'clock beam is traditionally made from a ribbed metal alloy 11 with the base of aluminum, and typically comprises, on the outer surface thereof, primary 13 and secondary 15 rails capable of allowing the movement of the associated half-cowl 7b (not shown), and a plurality of hinge yokes 17a, 17b, 17c, 17d capable of allowing the beam 1b to be hinged on the associated nacelle mast.
A receptacle 19, mounted on the upstream portion (relative to the direction of the flow of air in the nacelle) of the beam 1b, allows fastening of the associated front half-frame 3b designed to support the vanes 5b of the thrust reverser (frame and vanes not shown).
As shown in FIG. 5, the beam 1b is attached by riveting 20 on the upper portion of a fixed inner half-structure panel 18b, generally made from a composite material, and defining the cold air tunnel 9b with the associated thrust reverser half-cowl 7b. 
In particular out of a concern for savings in terms of mass, considerable work has been done in recent years to seek solutions using composite materials for the 12 o'clock and 6 o'clock beams, as well as for the front half-frames.
Thus, for example, prior art document US 2007/0294996 describes a composite 12 o'clock beam with the base of carbon fibers, with a closed and hollow section.
Although the beam disclosed by this document has a clear weight reduction, it requires complex molding operations.